U.S. Pat. No. 5,142,712 describes a modern vacuum assisted toilet wherein a vacuum created during a flushing, is coupled to the toilet bowl outlet to draw out the contents of the toilet bowl while water dumped into the toilet bowl pushes out the contents. The vacuum is created by placing a largely sealed container within the conventional toilet tank and allowing the water level in the container to drop as water is flushed from the tank, with the dropping water level creating a vacuum in the upper portion of the tank. Such vacuum assisted toilets allow the use of less water, as where it is decreased from 31/2 gallons to 1.6 gallons, while retaining a large diameter toilet outlet such as more than 21/8 inch, and while efficiently removing the contents of the toilet bowl.
There is a demand for low profile vacuum assist toilets, wherein the toilet tank extends a minimum height above the level of the top or rim of the toilet bowl. Where the tank is tall, such as more than fourteen inches above the top of the toilet bowl, it dispenses water with a large head, or pressure, and the water rapidly fills the bowl to efficiently flush it. If such an efficient flushing could be obtained using a tank of lower height, this would create a toilet of more attractive appearance.